The number of businesses owned by women increased 20 percent during a recent five-year period, according to the U.S. Census Bureau, while the revenues produced by those firms jumped 15 percent.

"It's important to note what a long way women have come," says Erin Fuller, executive director of the National Association of Women Business Owners (NAWBO). "The number of woman-owned businesses is now growing at twice the rate for all businesses, and we forecast that it's going to continue at that speed."

But these gains aren't occurring across the board. Women find some business communities more congenial than others. The key question is: Which places give a woman the best chance of starting a company or climbing the corporate ladder?

A new Bizjournals study has the answer. It puts the San Francisco-Oakland area at the top of the national rankings, followed by other high-profile urban centers such as Washington, New York City and Los Angeles, and the smaller college town of Madison, Wis.

Bizjournals used a nine-part formula to identify the markets that offer women the best business opportunities, both as entrepreneurs and employees.

The study focused on the nation's 100 largest metropolitan areas, which had 195.5 million residents as of mid-2006, accounting for 65 percent of the nation's total population. These areas included 4.5 million businesses owned by women, 69 percent of the national total.

The highest scores in Bizjournals' rankings went to markets where a substantial number of well-educated, well-paid women hold responsible positions in local businesses.

The San Francisco Bay area emerged as the clear national leader. The mix of industries in the San Francisco-Oakland area has made it possible for women to do extremely well, says Tucker Hart Adams, president of The Adams Group Inc., a Colorado Springs economic-research firm.

"Instead of heavy manufacturing, San Francisco has a lot of technology-related and service-related businesses," she says. "And it's a fact that you tend to find more women going into technology and the services, not steel plants. It also helps that San Francisco has a very supportive network for women in business. Instead of the good-old-boys network, it's a good-old-girls network."

San Francisco-Oakland is the only market to rank among the three national leaders in three of the study's key categories: the percentage of women who hold bachelor's degrees, the number of woman-owned businesses per 10,000 residents, and the share of female employees with salaries of $100,000 or more.

Second place belongs to Washington, reflecting the impressive education levels of its female residents. Forty-four percent of Washington's women have bachelor's degrees, and 19 percent hold advanced degrees. Both figures lead the nation.

America's two largest metros — New York City and Los Angeles — rank as the third- and fourth-best markets for women in business. One possible explanation, says Adams, is that the economic conditions in those sprawling areas give female executives extra inspiration to succeed.

"It's harder to be a one-income family in places such as New York or Los Angeles," she says. "They're so expensive that to live there, you probably have to have every adult in the household working."

Fifth place goes to Madison, which is both the state capital of Wisconsin and the home of the University of Wisconsin. The Madison area, with only 543,000 residents, is the smallest metro in the top 10.

Sixth through 10th on the list of America's best markets for women in business are Boston, Denver, Columbus, Atlanta and New Haven, Conn.

The Bizjournals study identified three qualities that these top-rated areas share:

"These are places with exciting business climates and strong population growth," NAWBO's Fuller says of the top-rated markets. "I think they tend to be more creative and more open to the advancement of women."

At the bottom of the standings is Ogden, Utah, which has the dubious distinction of being America's most unattractive market for women in business, according to Bizjournals' formula.

The wage gap between the sexes is wider in Ogden than in any other metro included in the study. The typical female worker in the Ogden area is paid 50 percent less than the typical male.

Ogden also ranks among the six worst markets in three other categories: women with advanced degrees, females with salaries of $100,000 or more, and the percentage of local managerial and professional jobs held by women.

A second Utah metro, No. 92 Salt Lake City, joins Ogden in the overall bottom 10, a trend that Adams attributes, in part, to the state's dominant religion.

"Utah is a heavily Mormon state, a very patriarchal society," she says. "It's a society where the expectations for women are different than in most other parts of the country."

Also mired in the bottom five are Bakersfield and Stockton, Calif.; Augusta, Ga.; and Palm Bay-Melbourne, Fla.